Activate Ashnod's Altar by sacrificing another creature, adding {C}{C}.
When the creature dies, Extractor Demon triggers, causing you to mill two cards if your graveyard is empty, or causing an opponent to mill two cards otherwise.
If your library is empty, activate Soldevi Digger by paying {2}, putting a card from your graveyard onto the bottom of your library.
Tormod triggers, creating a 2/2 Zombie creature token.
Repeat.

Infinite LTB

Infinite ETB

Infinite sacrifice triggers

Infinite death triggers

Infinite mill

Infinite self-mill

Near-infinite colorless mana

Tormod, the Desecrator

Extractor Demon

Ashnod's Altar

Soldevi Digger

Activate Ashnod's Altar by sacrificing another creature, adding {C}{C}.
When the creature dies, Extractor Demon triggers, causing you to mill two cards if your graveyard is empty, or causing an opponent to mill two cards otherwise.
If your library is empty, activate Soldevi Digger by paying {2}, putting a card from your graveyard onto the bottom of your library.
Quintorius triggers, creating a 3/2 Spirit creature token.
Repeat.

Quintorius, Field Historian

Activate Ashnod's Altar by sacrificing another creature, adding {C}{C}.
When the creature dies, Extractor Demon triggers, causing you to mill two cards if your graveyard is empty, or causing an opponent to mill two cards otherwise.
If your library is empty, activate Soldevi Digger by paying {2}, putting a card from your graveyard onto the bottom of your library.
Teval triggers, creating a 2/2 Zombie Druid creature token.
Repeat.

Teval, the Balanced Scale

Combos with "Extractor Demon"